Private investigator Tim McKinnel has worked with Mr Pora's defence team since 2009 and paid tribute to the family of Susan Burdett.

"We're mindful that when we first raised this case and started to work on it the impact that it was likely to have on them and and we've just tried to be as open an honest as possibly could be with them about what we were doing and why we were doing it."

Brother wants answers

Susan Burdett's brother has called the Privy Council's decision the only reasonable outcome.

Jim Burdett said he was "unsurprised" by the findings.

He told Morning Report he still wants answers to who really murdered his sister, and rather than looking at another trial for Teina Pora, energy would be better spent digging deeper.

Submissions on third trial

Mr Krebs told Morning Report that while Teina Pora has no restrictions on his liberty for the first time in 22 years he is still in something of a limbo.

"He's not on bail, he's not facing a charge, strictly, he's not on parole; we're just waiting to see whether the Privy Council will order a retrial."

The Privy Council has taken the unusual step of calling for submissions on whether there should be a third trial for Mr Pora. Crown and defence lawyers have four weeks to argue their case.

If after hearing submissions the Privy Council decided there would be no retrial that would be the end of the matter, said Mr Krebs. If the Privy Council decided there should be a retrial, the decision as to whether it takes place still rests with the Solicitor-General.

The Office of the Solicitor-General has said it will consult the police and Susan Burdett's family before deciding whether to argue for a retrial.

If there is no re-trial, the issue of Mr Pora's 22 years in custody and the possibility of seeking compensation will be looked at.

The ruling

The justices upheld the main branch of Teina Pora's appeal after four months of deliberation. They ruled new scientific evidence of a false confession raises the unquestionable risk of a miscarriage of justice.

In the formal decision, the Privy Council noted that much was made at both Mr Pora's trials of his confessions to police.

But the Privy Council received expert evidence from two medical experts, Dr McGinn and Dr Immelman.

Both gave evidence that concluded there was the risk of a miscarriage of justice and explained why Mr Pora's confessions may have been false.

"This is of central and critical importance to one's approach to the question whether his convictions can be regarded as safe.

"The impact that evidence of a confession will have, especially a confession to heinous crime, is difficult to overstate. The natural reaction to such an admission is that it is bound to be true. Why would someone confess to a dreadful crime if they were not guilty of it? But experience has shown that false confessions, even to the most serious of offences, are often made."

The Privy Council concluded: "the combination of Pora's frequently contradictory and often implausible confessions and the recent diagnosis of his FASD [fetal alcohol spectrum disorder] leads to only one possible conclusion and that is that reliance on his confessions gives rise to a risk of a miscarriage of justice.